Patent GB-1020316-A (GB)
Title: Electric heating film
IPC: H05B3/06
Filed: 1961-01-20
Abstract: 1,020,316. Making connections to electric resistance heating films. P. EISLER. Jan. 19, 1962 [Jan. 20, 1961], No. 11506/65. Divided out of 1,020,311. Heading H5H. A heating film, incorporating at least one conductive meander pattern consisting of substantially parallel conductive arms with narrow staggered elongated insulating spaces between the arms and bridges joining the ends of the arms, is provided with terminals formed at least in part by part of the conductive pattern and in, or capable of being brought merely by unfolding into, a form having a thickness of the same order as that of the material of the conductive pattern. The terminals may be longitudinal marginal areas wider than the said arms, or may be produced by securing additional conductive strips to selected areas of the pattern, or may be provided on a structure or material with which the heating film is used, the film being mounted in such a way that conductive connection is made between appropriate areas of the pattern and the terminals. In one form (Fig. 1, not shown) a film as described in the parent Specification has folded over marginal portions forming terminals. In Fig. 2 the margins 14 are cut along the dotted lines 56 to provide terminals 57 without waste of material. Fig. 5 shows an arrangement in which single fold bus-bars 27 of a plurality of heating film strips forming a floor-covering underlay are cut along narrow longitudinal uncrimped zones 36 as described in Specification 1,020,312 and the cut portions folded sideways at 37 to form two groups of bus-bars which are connected by links 39 to a transformer 41. The links 39 may comprise split metal tubes, the bared ends of the leads being inserted in the slot in the tube and the leads being wound around the tube and secured by a spring clip (Fig. 13, not shown). Paper-backed aluminium foil sheets 38 are inserted to insulate the crossing- points and to increase the conductive crosssection at these points to prevent hot spots. In modified arrangements (Figs. 7 or 11, not shown) the bus-bars 27 consist of a plurality of folds, the uppermost fold being cut and folded sideways. A paper covering is provided on one side of the film in these arrangements, the insulating sheets 38 being omitted. Additional strips of foil with or without a paper covering on one side may be inserted in the folds to contact the bare side of the film and may be perforated and secured in position by an adhesive. The films may be applied to any floor covering or to the ceiling or walls of a room. Figs. 15 and 16 show a terminal arrangement for making connection to wallpaper hung in widths incorporating heating films having longitudinal bus-bars either integral, applied, or on a separate underlay. Two crimped foil strips 71 and 72, connected respectively to the two poles of the supply, are secured to paper insulation 73 by adhesive and separated by a flexible layer of insulation 74 from mounting plates 75 hinged at 76. Apertures 77 wider than the width of two bus-bars are provided in the foil 71, and smaller apertures 78 are provided in the paper 73, at intervals equal to two widths of the wallpaper. The plates 75 are provided at intervals equal to one width of wallpaper, and are secured along the wall by their lower halves. When the wallpaper is placed in position and the upper halves of the plates 75 folded down, alternate pairs of bus-bars make contact with foil 72 through the apertures, the intervening pairs of bus-bars making contact with foil 71. The plates 75 are secured in their folded position by nails driven through the holes provided or alternatively driven through the plates at the positions of the apertures 77. Apertures 81 may be provided in the foil 72 for the same purpose. The connecting arrangements described may be applied to films mounted on any surfaces which are to be heated, e.g. interior surfaces of motor vehicles or cabins, table tops, packages, pipes, or moving belts. In Fig. 18 a gap 59 is provided across the pattern leaving the marginal arms 61 intact, and the severed arms on each side of the central gap 62 are connected together by a conductor 63 e.g. a foil strip soldered, welded, crimped or stuck to the arms, to form terminals.